The present invention generally relates to a unique construction for a digital signal cross connect having relatively high signal transmission rates. More specifically, the invention relates to a unique modular configuration of a digital signal cross connect module having relatively high digital signal transmission rates which allows it to be mounted on a network bay frame commonly used in mounting digital signal cross connects having substantially lower signal transmission rates.
In many modern telecommunications systems, most of the older analog communications signaling equipment has been replaced by corresponding digital equipment. The digital communications signaling equipment is desired because of its greater clarity and speed of transmission.
The digital communications equipment is directly compatible with other modern technologies. For instance, many modern offices utilize facsimile machines for transmitting documents, or other printed matter over telecommunications networks. Many, if not all, facsimile machines utilize digital technology in order to convert the printed images on a document into signals that can be electrically or electronically transmitted from one place to another. Additionally, many places of employment and institutions of higher learning utilize computers having access to other computers, such as through a DEC-NET.TM. network, or to large databases, such as MEDICUS.TM. and WESTLAW.TM.. The computers and their connecting modems themselves are completely digital in construction and operation, and the access they have to the other computers and databases is made over a telecommunications network. Therefore, it is highly desirable to have a telecommunications network that is also based on digital technology.
By using a digital telecommunications network in conjunction with other digital equipment, such as computers, the operation of the digital equipment becomes more precise, accurate, and has greater celerity. The digital telecommunications lines, switches, and other equipment allow for greater transmission clarity and faster transmission speeds than their older analog counterparts. The benefits of digital telecommunications technology is enjoyed not only by businesses having computers and facsimile machines, but by every user of the digital telecommunications network. Human voices are usually clearer when transmitted through digital equipment. Often the voices are so clear that the person on the other end of the line sounds as though he is in the same room.
However, digital equipment, especially in the computer field, is quickly advancing. New innovations in digital technology occur almost daily. Accordingly, digital telecommunications systems must keep up with that rapid pace of advancement. Additionally, as more and more users are added to a telecommunications network, the equipment must become capable of operations at greater and greater speeds in order to keep up with the enhanced workload. Thus, digital telecommunications equipment that was state-of-the-art today may become obsolete tomorrow.
A consequential effect of the rapid advancement of digital technology is that certain digital equipment must be replaced from time to time to allow for newer, faster, more advanced equipment. This is especially true in switching and connecting equipment. For instance, a digital signal cross-connect having a transmission rate of 1.54 megabytes per second (Mb/s) might have to be replaced by a digital signal cross-connect having a transmission rate of approximately 45 Mb/s or even approximately 274 Mb/s. Often, the second digital signal cross-connect is incompatible with the other existing telecommunications equipment and/or its supporting superstructure. Thus, in order to utilize the faster transmission rates of the second digital signal cross-connect, the older cross-connect would have to be removed along with its supporting superstructure.
This constant replacement process has become cost prohibitive due to the waste of the superstructure and the intensity of labor involved. The cost prohibiting factors are again encountered if a 45 Mb/s cross-connect must be replaced by a digital signal cross-connect having a transmission rate of approximately 274 megabytes per second. The time needed to replace the equipment represented lost revenues to the telecommunications firms because the communications network, or a portion thereof, would be down for a certain time period. Also, because the entire superstructure had to be replaced, the number of customers inconvenienced by the equipment upgrade was substantial, leading to greater lost revenues. In order to keep the costs of equipment replacement as low as possible, the present invention provides a uniquely constructed digital signal cross-connect device which is compatible with an existing digital cross-connect superstructure. The uniquely constructed digital signal cross-connect fits directly into the apertures and spaces which were designed to accept older and slower digital equipment. Specifically, the digital cross-connect of the present invention has an external mounting configuration or "footprint" which allows it to be mounted in the rack space designed for, or previously occupied by older equipment and in substantially the same fashion as the older equipment. With the use of the digital signal cross-connect, constructed according to the teachings of the present invention, newer, faster digital equipment can be installed either together with existing equipment or as a replacement of older equipment without having to remove or re-configure the existing telecommunications superstructure, thereby reducing down time and lost revenues.